1. Field of the Invention
The present invention relates to a document feeder.
2. Description of the Related Art
Some image-reading apparatuses for documents include a feeder for performing an intended processing while conveying a document. In such image-reading apparatuses including a feeder, a document placed on a tray or the like can be sequentially conveyed by rollers and the conveyed documents can be sequentially read. In such a feeder included in image-reading apparatuses, vibration occurring during conveyance of the document, which may cause poor images, needs to be avoided. For that purpose, some conventional feeders include a member for providing a document being conveyed with a biasing force for the purpose of reducing the vibration of the document. To provide a biasing force on a document for reducing the vibration of the document, some methods have been developed such as adding a biasing force by a movable member, and adding a biasing force by a guiding protrusion (refer to Japanese Patent Application Laid-open No. 11-222336, Japanese Patent Application Laid-open No. 10-271271, Japanese Patent Application Laid-open No. 04-208764, and Japanese Patent Application Laid-open No. 2001-350299, for example).
When the vibration of the document is reduced by adding a biasing force on a document, the conveyance of the document is likely to be obstructed.